The Iziz defense towers constituted a network of battle stations engineered for the safeguarding of the walled city of Iziz. Iziz served as the capital and sole settlement located on the Inner Rim world of Onderon. These towers were equipped with long-range energy weaponry, including turbolasers and ion cannons, enabling them to effectively counter both ground and air based enemy actions.
During 4000 BBY, the defense tower system played a role in the Battle of Iziz, where they were deployed against the Beast Riders originating from Onderon's wilderness. Following the extensive destruction of Iziz in that battle, these emplacements were lost. Approximately fifty years later, a new system of air defense towers was constructed to replace them. This updated defensive network was utilized during the Onderon Civil War, at the time of the Jedi Exile's return to Onderon. Her mission was to support Queen Talia in suppressing the Sith-supported coup d'état orchestrated by her cousin, General Vaklu.
As planetary emplacements, defense towers were constructed along the defensive walls of Iziz, the capital city of Onderon. The towers were armed with both long-range turbolaser batteries and ion cannons. Wave gunners, members of Iziz's army, operated these weapons from rotating platforms. The towers were specifically built to engage the flying beasts ridden by the Beast Riders from the Onderon wilderness. While providing significant protection against ground assaults, the defense towers were more vulnerable to aerial attacks, as their open tops allowed for greater firing arc. However, the towers were easily destroyed when subjected to precision strikes from the Beast Riders' heavy blaster rifles.
The uppermost section of the tower housed the turbolasers and ion cannons, allowing for a complete range of motion when targeting drexls or enemy aircraft. Laser fire from the batteries was a concentrated beam of yellow energy, capable of eliminating a Drexl-mounted Beast Rider with a direct hit. Furthermore, the recharge time between turbolaser blasts was relatively short. This enabled the Wave gunners to maintain a constant barrage on targets, inducing apprehension among approaching enemies and causing them to reconsider their attack strategies. A new network of defensive structures was established sometime before 3951 BBY. These towers were enclosed structures, manned by at least four gunners, led by an officer, and equipped with a pair of laser cannons each.
In 4000 BBY, Iziz requested assistance from the Galactic Republic, which dispatched several Jedi Knights to help quell the long-standing civil war that plagued the planet. Upon arrival, the Jedi were ambushed by Oron Kira's Beast Riders, who had prior knowledge of their coming. The Jedi immediately requested support from the city, and the defense towers responded by opening fire with their batteries, shooting down several of the pursuing Riders.
During the Battle of Iziz in the same year, the defense towers were once again used against the Beast Riders, now led by Oron Kira's father, the Beast-Lord Modon Kira. Four defense towers were positioned along Iziz's northern wall, making them the first to engage the approaching Beast Riders. Upon spotting their advance, Queen Amanoa of Iziz instructed her servant Novar to order the Wave gunners to fire their turbolasers and ion cannons in an attempt to repel the attack. The gunners followed her orders but were quickly overwhelmed by the Beast Riders' massive army, the largest the city's inhabitants had ever witnessed. As the Beast Rider ground troops advanced over the city ramparts, some managed to scale the defense towers. Gunner 1, the Wave gunner in the first tower, noticed the Beast Riders preparing to attack the fourth tower and commed Gunner 4 to warn him. Gunner 4 received the static-filled message just as the first defense tower was destroyed by incoming blaster fire. The transmission cut out as Commander Gobee of the Beast Riders appeared behind him. Gobee then shot the gunner down while taunting his fallen comrade, Gunner 1. The remaining defense towers were destroyed near the end of the battle, when the forces of Iziz were defeated.
By the time the Jedi Exile arrived on Iziz nearly fifty years later, a network of air defense towers had replaced the original defense towers. During the Onderon Civil War's second battle, these towers attempted to destroy a modified Basilisk war droid loaned to the Exile by the Mandalorians under Mandalore Canderous Ordo. She used the droid to return to the planet and relieve Onderon Royalist forces protecting Queen Talia. The towers' efforts were unsuccessful, as the vehicle was too fast and heavily-armored to be destroyed. The Exile and her allies successfully landed in the ruined Merchant Quarter and engaged troops loyal to General Vaklu's Sith-backed coup attempt. After Royalist forces killed its crew, the Exile hijacked one of these towers and used it to shoot down several Vaklu-aligned Aurek fighters that were attacking Royalist positions within the Iziz Royal Palace.
The towers initially appeared in the Tales of the Jedi story arc Ulic Qel-Droma and the Beast Wars of Onderon, and were mentioned in the audio dramatization. They reappear in the computer and video game Star Wars: Knights of the Old Republic II: The Sith Lords, but their structure is depicted differently. Captain Riiken refers to them as "air defense towers" in the game's dialogue. Additionally, the officer provides the player with a brief overview of the Beast Wars if asked.